DESCRIPTION (provided by investigator): Preventing chronic obstructive pulmonary disease (COPD) exacerbation is the most important method for prolonging the productive life of COPD patients, and rapid response to respiratory infection is known to reduce the severity of exacerbations. At least 2 environmental exposures may also trigger exacerbations - tobacco smoke (both active and passive smoking) and urban air pollution. Beyond these, little is known about exposures to respiratory irritants and other pollutants in the home, community and work that might exacerbate COPD. Studies of asthma, bronchial hyper reactivity and acute loss of pulmonary function have reported common and substantial indoor exposures to respiratory toxins including irritants, with effects similar to if not stronger than those reported for urban air pollution. We hypothesize that reducing exposure to agents associated with asthma and other acute respiratory effects may also reduce exacerbation frequency in COPD patients. This pilot study will use a case-crossover design to identify triggering environmental exposures in the days immediately preceding an exacerbation by comparing these exposures to those in randomly chosen weeks when participants are not experiencing exacerbations. Because no validated survey instrument has been identified for this purpose, we will develop an interviewer-administered questionnaire to gather data for the previous week on exposures to respiratory irritants and particulates as well as on activities generating these exposures in the home, community and work. Questions will be drawn from published instruments assessing whether and how often the exposures of interest were encountered, or the exposure-generating activities occurred. The study population will be 200 COPD patients enrolled in the disease management group of a large health maintenance organization. The population will be followed for 1 year. We expect that on average we will gather data on 1 exacerbation and 3 referent periods for each of the 200 participants. COPD patients are instructed to phone a nurse whenever they notice the onset of an exacerbation. Telephone interviews will be conducted at these times, as well as at least 3 other random times during the year. Exacerbations will be clinically confirmed by a trained clinician using standard criteria which consider increased severity of signs and symptoms as well as changes in medication usage. The intervew will gather data on respiratory symptoms and exposures in the home, community and work, including both active and passive smoking. This pilot study will identify evidence supporting future research with quantitative exposure assessment of specific chemical agents. The proposed study would be the first to use the powerful case-crossover design to identify environmental triggers of COPD exacerbation, potentially leading to important new strategies for prevention of this severe and disabling disease. PUBLIC HEALTH RELEVANCE: We hypothesize that air pollutants associated with asthma and other acute respiratory effects in the home, community and workplace may trigger exacerbation of COPD. The proposed research will study members of a COPD disease management group, and use a case-crossover design to identify triggering environmental exposures in the days immediately preceding a clinically confirmed exacerbation by comparing these exposures to those in randomly chosen weeks when patients are not experiencing exacerbations. The proposed study would be the first to use the powerful case-crossover design to identify environmental triggers of COPD exacerbation, potentially leading to important new strategies for prevention of this severe and disabling disease.